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Several pathways can be identified for contaminant migration from the site.

Aerial Migration to the Residential Neighborhood of On-site Contaminants Adsorbed to Soil Particulates:

Contaminants adsorbed onto soil particulates can become airborne; some contaminants
with suitably high vapor pressure may volatilize, or solvents containing pesticides may
volatilize and carry the pesticide with them. Although a gravel layer was applied in
1983 as an interim cleanup measure, results from air monitoring in 1988 indicated that
the action was insufficient to prevent DDT migration into air on-site and off-site (see
On-Site Contamination and Off-Site Contamination). Because the gravel layer appears
to have been removed from the middle area of the site, it is likely that even greater
amounts of contamination are migrating into the air than were measured in 1988. The
passage of large trucks drawing trailers across this area (see Site Visit) may further the
aerial transport of DDT on-site and off-site.

The wind reportedly prevails from north to south, and the secondary direction is from
the northeast, toward the residential area (Ecology and Environment, Inc. CERCLA
Expanded Site Inspection, February 1989). An elevated freeway now occupies the area
where the first block of houses once stood, possibly disturbing the air currents either to
reduce contaminant deposition into the soils of the neighborhoods or to increase
deposition by reducing the air flow. At this time the effect of the freeway on continued
soil deposition in the residential area is unknown.

Contaminants from the site have migrated into the sediments of the Lauritzen Canal and
the Santa Fe Channel. An EPA Emergency Removal Action in November 1990
removed portions of the canal embankments that contained up to 1,000,000 ppm total
DDT (pure DDT), 146 ppm aldrin, and 1,050 ppm dieldrin (see Table 5).

Samples in 1988 of the Lauritzen Canal sediments, which were dredged in 1984-85,
approximately 200 feet south of the electrical substation, have shown concentrations
greater than 100 ppm total DDT (see Table 7 and Figure 3). DDT may currently
migrate into the Lauritzen Canal due to tidal influences, storm water runoff, and wind.
When the plant was operational, DDT was also discharged into the canal during floor
washings and "overflow" from DDT settling tanks. United Heckathorn had a permitted
discharge of wastewater of 3,500 gallons/day (letter to Robert Jones from Richard
Lovejoy, Department of Public Works, City of Richmond, 1960, Reference 17 in EPA
file).

Migration of On-Site Contaminants Through Groundwater into Lauritzen Canal
Sediments:

Groundwater beneath the site contains chlorinated pesticides and lead at concentrations
exceeding their MCLs. Although groundwater flow is complex due to the different
types and amounts of fill material placed on the site, an average of 390 gallons/day was
estimated to seep into the Lauritzen Canal (Harding Lawson Associates, 1986). This
seepage carries contaminants from on-site upland locations into the Lauritzen Canal
sediments where they persist, accumulate, and become constituents of benthic
organisms, which are eaten by fish.

Migration Through Surface Water into Lauritzen Canal Sediments of On-site Contaminants Adsorbed to Soil Particulates :

No data were identified on contaminant concentrations in the Lauritzen Canal, Santa
Fe Channel, or Richmond Inner Harbor, but surface water runoff from the embankment
would be expected to carry soil containing DDT and heavy metals. Since DDT is
practically insoluble in water and binds tightly to organic material, it is likely to remain
in the sediment. Lead and heavy metals are insoluble in the inorganic molecular form,
but bacterial action in sediments may create soluble organic compounds which could
then migrate via surface water or be taken up by organisms.

Although a limited number of samples was taken (see Off-Site Contamination), data
indicate that DDT has migrated from soils on-site to Lauritzen Canal sediments, and
that bioaccumulation is occurring both in benthic organisms and in fish (Aqua Terra
Technologies, 1984; Hayes and Phillips, 1985, 1986, and 1987; United Anglers, 1986).
An indirect indication of DDT bioconcentration and bioaccumulation in fish and in
benthic organisms is the significant increase in the DDT metabolite, DDE, in the livers
of diving ducks called scoters during their winter stay around Richmond Harbor
(Ohlendorf et al., 1991, and Off-Site Contamination Section).

B. Human Exposure Pathways

Complete pathways through which human exposure has occurred and is occurring appear
in Table 9 (next page) and are discussed below.

The first pathway is migration of organochloride compounds and heavy metals into
airborne dust which may be inhaled.

The second pathway is deposition of airborne organochloride compounds and heavy
metals in soils of play areas, gardens, and playgrounds, and on the skin of workers.
Contaminated soil on hands may be ingested during normal hand to mouth
movements while gardening or eating, or in the case of children, actually eating sand
and soil.

The third pathway is migration of organochloride compounds and heavy metals into
sediments of the Lauritzen Canal, allowing accumulation in benthic organisms
(worms and clams) and bioaccumulation in fish that eat worms. Subsequent human
exposure may occur through eating contaminated fish.

TABLE 9. COMPLETED EXPOSURE PATHWAYS

Time

1. Source of Contamination

2. Environmental Media & Transport

3. Route of Exposure

4. Point of Exposure

5. Receptor Population

1a. Past & Present

Contaminated Upland Soil

Airborne Dust

Air On-site

Inhalation

On-site workers

b. Past & Present

Contaminated Upland Soil

Airborne Dust

Residential Soils

Inhalation

Adults & Children

2a. Past & Present

Contaminated Upland Soil

Airborne Dust

Air On-site

Ingestion

On-site workers

b. Past & Present

Contaminated Upland Soil

Airborne Dust

Residential Soils

Ingestion

Adults & Children

3a. Past & Present

Contaminated Upland & Embankment Soils

Airborne Dust

Lauritzen Canal Sediments

Ingestion of Shellfish and Fish

Workers, Adults, & Children

b. Past & Present

Contaminated Upland & Embankment Soils

Groundwater

Lauritzen Canal Sediments

Ingestion of Shellfish and Fish

Workers, Adults, & Children

c. Past & Present

Contaminated Upland & Embankment Soils

Tides & Surface Runoff

Lauritzen Canal Sediments

Ingestion of Shellfish and Fish

Workers, Adults, & Children

Human beings can be exposed to chlorinated pesticides such as DDT and dieldrin
and to heavy metals such as lead through more than one of these pathways simultaneously.
The following paragraphs discuss the environmental pathways through which adult
and child members of the community may be exposed, or through which on-site
workers may be exposed.

Air monitoring performed in 1988, when the site was covered with gravel, showed that
airborne dust contained DDT (Tables 1 and 2). As the data in Tables 1 and 2 show, the
highest contaminant concentrations are present over a "hot spot," the former
United Heckathorn Building 1. Since large trucks still traverse the area where Building
1 was located (as described in the Site Visit section), the gravel layer has been disturbed,
and it might be expected that increased concentrations of airborne DDT would be
measured if monitoring were done. Therefore, workers on-site may be exposed to much
higher contaminant concentrations than the surrounding community. However,
permissible exposure concentrations are higher for workers than the residential
population since workers usually include only healthy persons who are exposed for an
eight-hour workday.

Workers, however, may be exposed to site contaminants through several pathways at
the same time. Airborne dust may settle on the skin of workers, allowing some DDT
to be absorbed, although DDT is poorly absorbed through the skin compared to other
organochlorine pesticides. There may be increased ingestion of DDT and heavy metals
such as lead, and inhalation and dermal absorption of DDT, endrin, and dieldrin due to
activities on the site. As described in the Site Visit section, workers appear to have been
eating lunch on or near the site. In adults, inadvertent ingestion of soil may result in
ingestion of about 100 mg/day of soil containing DDT, dieldrin, endrin, and lead.

Airborne dust containing contaminants was measured at a station on the boundary of
residential areas north of the site when air monitoring was done (Table 6). As discussed
before, at that time the site was inactive and the gravel layer was undisturbed. The
airborne concentrations measured at that time were at exposure levels considered safe
(see Appendix A). However, the actual airborne concentrations were undoubtedly
higher when the site was used to grind DDT and other pesticides; they were likely to
have been higher before the site was temporarily remediated with a gravel layer, and
they may have become higher once the gravel layer was disturbed by grading and by
heavy vehicles driving over upland areas that contain contaminants. Sampling of
current levels of contaminants in soils, coupled with data on rates of deposition from the
Ecology and Environment monitoring, may allow crude estimation of cumulative past
rates of inhalation exposure.

Furthermore, inhalation of airborne dust is only one way people in the residential areas
may be exposed. Airborne DDT and such heavy metals as lead, which were blown off
the site, may have been deposited in the soils of the residential neighborhood. A second
potential human exposure pathway of concern is ingestion of soil contaminated with
those compounds by children playing in the soil around their homes, or by adults
gardening. This is a particular concern because the rate of deposition may have been
especially high when the United Heckathorn plant was operational; because these
contaminants are persistent in soils, and because the air monitoring conducted by
Ecology and Environment was performed after the site had been abandoned and had had
temporary remediation. The present rate of deposition has been altered again by the
activity on site, and by construction of the elevated Hoffman Freeway between Cutting
Boulevard and Virginia Street, and by disturbing the gravel, which constituted part of
the temporary remediation. Sixth Street and Virginia Street are now on the other side
of the elevated freeway, and Virginia Street no longer extends to Fourth Street. The
elevated freeway may alter air flow patterns, and thus deposition of DDT in
neighborhood soils. These variables make it impossible to accurately estimate exposure
concentrations without sampling soils in the residential neighborhoods.

Adults and children living in the residential neighborhoods may also be exposed to
chlorinated pesticides by eating contaminated fish and seafood. The limited sampling
of fish discussed in the "Off-Site Contamination" section indicates that worms and clams
have high concentrations of DDT accumulated from the sediments of the
Lauritzen Canal, and that fish have bioaccumulated DDT by eating these worms and
clams. Although fish sampling has been insufficient, the fact that migratory scoter
ducks in Richmond Harbor accumulate high concentrations of DDE after eating local
fish for only about three months indicates that DDT levels in local fish are high (see Off-Site Contamination).

There are also data from the State Mussel Watch Program (see Off-Site Contamination)
showing that resident and transplanted worms, mussels, and crabs in the Lauritzen Canal
and in the Santa Fe Channel contained the highest levels of DDT observed along the
California coast. The levels far exceeded the elevated toxic pollutant levels (ETPL)
encountered in 95 percent of all mussels transplanted to bays along the western
California coast as well as FDA action levels.

The shiner surf perch caught by the United Anglers from the Lauritzen and Parr Canals
showed body burdens of DDT exceeding the FDA action level. Unfortunately the
number of fish is too limited to accurately estimate the range of exposure by this
pathway. However, life-time consumption of fish with DDT concentrations equal to that
of the shiner surf perch would produce a moderate increased cancer risk (see Appendix
B). Lower concentrations were found in other fish species but there was a very small
total number of fish caught. Nevertheless, concern about human consumption of the
marine species with similar DDT concentrations caused DHS to direct LRTC to post
warning signs along the site's perimeter fence, along the canal, and at the north end of
the canal in October 1986. The signs, in English and Spanish, say that channels,
sediments, and shellfish are contaminated with DDT and that fish may also be
contaminated with DDT (Tetra Tech, Inc., Revised Community Relations Plan LRTC
Site, 1988).

It is important to note that the use of the FDA action levels as a safe level of DDT in fish
for human consumption is in itself questionable. The action levels are concentrations
at or above which the FDA will take legal action to remove contaminated fish or
shellfish from the market. They do not represent permissible levels of contamination
where it is avoidable (Hayes and Phillips, 1986). They are based on several assumptions
that may not be true for members of a community who consistently catch local types of
fish from a particular place. The FDA action levels are based on the assumption that
a person eats fish and shellfish caught throughout the country rather than from one
location, and that consumption of individual species of fish is in proportion to the
percentage of that species caught in the commercial fishing industry. Therefore, the
FDA action level would be too high for an individual who frequently caught and ate a
particular local fish, which was not caught in large numbers commercially.
Furthermore, as stated before, the FDA action levels are not intended to be considered
safe levels.

Although it is unlikely that people fish in the Lauritzen Canal itself, fish are reported to
migrate between Point Richmond, the Brooks Island area, the Santa Fe Channel, and the
canal (Danny Reno and Keith Long, California Fish and Game, personal
communication, September 1990). Chip Demerest, Coastal Resources Coordinator
(NOAA), reported that he observed people apparently doing subsistence fishing in the
same spot on the Santa Fe Channel during his two visits to the site within the last eight
months. Fred McCollum, park ranger at Brooks Island, reported that he observes two
to four boats per day fishing in an area within 300 yards of the Lauritzen Canal. He
said that they appear to be repeat fishermen who launch their small boats at the
Richmond Marina about five minutes from the Lauritzen Canal.

Surface water is not considered a human exposure pathway of concern.

PUBLIC HEALTH IMPLICATIONS

Human beings may be exposed to chlorinated pesticides and heavy metals from the site
by inhaling contaminated airborne dust, or by eating fish that have bioaccumulated
DDT. There are insufficient data to determine the actual exposure concentration by any
pathway, but any one pathway may not be high enough to warrant health concerns.
However, people who live in the community may be exposed to site contaminants by
several routes simultaneously, and multipathway analysis may demonstrate exposure
concentrations of concern.

A. Toxicological Evaluation

Actual hazards associated with exposure to chlorinated pesticides and heavy
metals cannot be evaluated without data on the levels of those contaminants.
The following information from the ATSDR Toxicological Profiles provides
some information on the general toxicity of contaminants at the United
Heckathorn site. The toxic effects described in the following section are not
necessarily effects that would be expected from exposure to contaminants at the
concentrations found at the United Heckathorn site.

Toxicology of Site Contaminants:

DDT, DDD, and DDE: DDT is an insecticide used for control of malaria and typhus.
It is classified by EPA as a B2 carcinogen, a probable carcinogen in human beings,
based on the induction of malignant liver tumors in several strains of mice. DDT
produced only benign liver tumors in rats. There is no evidence from epidemiological
studies that DDT causes cancer in human beings. It was banned in 1974 because of
concern about the accumulation of DDT and its stable metabolites, DDD and DDE, in
the environment, and its reproductive toxicity in animals, especially birds. There was
also concern that it might cause reproductive toxicity in humans, because it was
accumulating to high levels in human fat tissue. Ingestion of 35 mg/day, approximately
0.5 mg/kg/day, for an adult for up to 25 months showed no ill effects. However,
ingestion of 10 mg/kg/day causes toxic effects in some people, but not in everyone.
DDT has toxic effects on the gastrointestinal tract, the heart, and the nervous system.
The effects on the nervous system are the consequence of slowing the turning-off process
of sodium conductance across the nerve membrane, resulting in tremors, irritability,
dizziness, apprehension, and disturbed equilibrium. At doses of 16 mg/kg, convulsions
frequently occur. Inhalation of 214 ppm DDT results in headaches and nausea; at 357
ppm vomiting also occurs; at 560 ppm heart rate increases, and at 571 ppm convulsions
occur (ATSDR, April, 1989).

Exposure to DDT for periods ranging from two to eight weeks has effected the
immunological system in humans and in animals. Exposure to 0.07 mg/kg/day caused
an increase in antigen titers in response to Salmonellatyphimurium in humans, and
13mg/kg/day produced the same effects in mice. The effects were not serious. A serious
immunological effect, thymus atrophy, was caused by 0.18 mg/kg/day in rabbits, and
121 mg/kg/day in rats (ATSDR, April, 1989).

Such serious developmental effects as slow development, slow learning, or decreased
growth rates were observed in animals given 0.02 mg/kg/day to 26 mg/kg/day.
Decreased fertility, decreased number of fetuses, or decreased numbers of litters were
observed in two generations of animals given 0.02 mg/kg/day to 0.91 mg/kg/day DDT
for 28 days (ATSDR, April, 1989).

Aldrin/Dieldrin: Aldrin and dieldrin are cyclodiene pesticides. Aldrin is readily
converted to dieldrin in the environment. Dieldrin was banned in 1974 by EPA because
of persistence in the environment and because of carcinogenic effects on animal livers.
EPA classifies both aldrin and dieldrin as B2 carcinogens, or probable carcinogens in
hyman beings. Studies on 235 workers exposed to 33.2 ug/kg/day aldrin and dieldrin
for 12.3 years at a Shell Chemical Company plant in Holland did not show any
carcinogenic effects. However, the time period for the follow-up is considered
inadequate to see any appearance of cancer (ATSDR, October, 1991).

Dieldrin causes such adverse reproductive effects in animals as reduction of litter size
and decreased fertility and ovulation at concentrations that do not cause maternal
toxicity. There are no comparable studies in human beings.

An increase has been reported in the blood concentration of aldrin/dieldrin (33 ppb vs
5.6 ppb) in mothers of stillborn infants compared to that in mothers of liveborn infants,
but the data are considered inconclusive (ATSDR, October, 1991).

Dieldrin is reported to be an active suppressor of cell mediated immunity at 5 ppm in
mice, due to impairment of macrophage antigen processing. However, there are no data
for human beings.

Endrin: Endrin is also a cyclodiene pesticide. It is not classified a carcinogen. Endrin
has a high acute toxicity in animal studies. In dogs, the NOAEL is 1 ppm and the
LOAEL is 2 ppm. Endrin is rapidly adsorbed through the skin, and it poisons the
central nervous system and the liver. Endrin is also reported to produce malformations
when given to mammals during pregnancy, and to have immunotoxic effects. Ingestion
of 6,000 ppm of endrin, a much higher dose than generally encountered in the
environment, caused convulsions and death.

An epidemiological study to examine the cause of death of workers employed in
manufacturing organochlorine pesticides, including endrin, showed no statistically
significant increases or decreases in the number of deaths from any specific cancer site.
However, the follow-up time was only 12 years, and the latency period for appearance
of cancer is considered greater than that. Increased numbers of deaths among factory
workers were seen due to pneumonia and other non-malignant respiratory diseases
(ATSDR, December, 1991).

Lead: Lead is an element that affects the nervous system, the heme-hemoprotein
system, the kidneys, and the reproductive system. Developmental defects are seen at
very low levels: decrements in I.Q. are seen in children of women with only 10-16 ug
lead/dl of umbilical cord blood. Alterations in heme synthesis occur when
concentrations of lead in blood reach 15 to 30 ug/dl. The concentration of free
erythrocyte protoporphyrins is often used as an indicator of exposure. Anemia occurs
at 75 ug lead/dl blood in children and at 80-85 ug lead/dl blood in adults. Calcium,
phosphate, and iron may affect absorption of lead (ATSDR, October, 1991).

The risk of premature birth increases fourfold as cord or maternal blood lead levels
increase from less than 8 to greater than 14 ug/dl. The range of 10 to 15 ug/dl is
considered to be the LOAEL in humans, and this developmental toxicity is manifested
as neurobehavioral deficits and reductions in gestational age and birth weight. Lead in
humans is associated with reproductive toxicity resulting in such symptoms as
miscarriages and decreased fertility, and with sperm abnormalities at 40 to 50 ug/dl. In
rats, developmental reproductive defects are seen at 18 to 29 ug/dl in females and 30
ug/dl in males. There is no conclusive evidence about teratogenic effects.

Arsenic: Arsenic is an element that has been classified as a carcinogen in humans (class
A) on the basis of human epidemiologic data (EPA Carcinogen Assessment Group). For
non-carcinogenic effects, doses as low as about 1-4 mg/day (20 - 60 ug/kg/day) in
human adults produce one or more characteristic signs of arsenic toxicity, such as
gastrointestinal irritation, anemia, neuropathy, skin lesions, vascular lesions, and hepatic or renal injury.

Chromium: Chromium is found in two states, trivalent (III) and hexavalent (VI).
Chromium III is considered almost innocuous, and it is an essential nutrient at 50-200
ug/day (0.7-3 ug/kg/day) in adult humans. Chromium VI, has been classified as a
known carcinogen in humans due to increases in mortality from cancers of the
respiratory tract in workers exposed to aerosols containing chromium. Inhalation of
0.002 mg/m3 chromium can cause nasal irritation and mild lung effects. Chromium is
poorly absorbed from the digestive system of humans, and chronic oral studies in rodents
are inconclusive. While some studies in rodents have not identified adverse effects on
toxicological endpoints, other studies have reported that, at high oral doses in female
mice, chromium attacks the digestive system by causing hemorrhaging, ulceration, and
tubular necrosis of the kidneys. In order to be consistent with a policy to protect public
health, chromium is assumed to be carcinogenic by ingestion as well as by inhalation,
but the potencies may vary by several orders of magnitude.

B. Health Outcome Data Evaluation

Complete human exposure pathways for on-site workers and adults and children in the
community do exist at the United Heckathorn site. A number of community concerns
have also been identified related to the site and other hazardous waste sites in the area.
However, the data are insufficient to determine the actual exposure concentration for
specific pathways at this time. Additional information or data on exposure point
concentrations will be necessary to determine whether it is possible or necessary to better
define possible health effects using health related data.

Health data that may be relevant to the United Heckathorn site include data from the
Cancer Surveillance Program and the California Birth Defects Monitoring Program.
Due to recent budgetary cutbacks for these two programs, our ability to get that
information is severely limited. If community concern regarding adverse health effects
is expressed or additional data suggests that adverse health outcomes are plausible, we
will request information from these two programs, review it, and incorporate our
findings in a future public health assessment of this site.

C. Community Health Concerns Evaluation

We have addressed the community concerns about health as follows:

1. Is it safe to eat fish caught in the Lauritzen Canal?

No. DTSC has posted signs warning people not to eat fish caught in the canal. There
is an indication that fish in the area of the Lauritzen Canal and nearby harbor have
gradually accumulated DDT in their bodies by eating worms and clams that have high
concentrations of DDT from the sediments of the canal (see discussion in the "Off-site
Contamination" section). DDT enters the body when a person eats food that has been
contaminated with DDT. Once inside the body, DDT is stored most readily in the fatty
tissue and takes a long time to leave the body. EPA is considering having additional
analyses of fish and benthic organisms included in its workplan (see Public Health
Actions #1).

2. Should the nearby neighborhoods be concerned about the possibility of dust blowing
off the site?

Airborne dust represents one way people in the residential areas could be exposed to
contaminants. Airborne DDT and heavy metals such as lead may have blown off the
site and deposited in the soils of residential neighborhoods. EPA is considering taking
soil samples in residential neighborhoods and monitoring air levels for DDT and heavy
metals.

CONCLUSIONS

Based on the available information, this site is considered a public health hazard because
evidence exists that exposures to chlorinated pesticides and heavy metals have occurred,
are occurring, and are likely to continue to occur through the exposure pathways
described above. Although sufficient environmental sampling data are not available to
estimate exposures, it appears likely that people could be simultaneously exposed to
DDT and other contaminants through multiple pathways such as eating fish, inhaling
soil dust, and inadvertently ingesting soil.

The upland soils where the DDT grinding and pesticide formulating operations of the
United Heckathorn Company were carried out, and the embankment of the Lauritzen
Canal are contaminated with chlorinated pesticides such as DDT, DDD, DDE, aldrin,
endrin, dieldrin, and with heavy metals, principally lead.

The areas of the embankment that were heavily contaminated with DDT were removed
as part of an Emergency Response. Because these areas appeared subject to erosion by
high tides and storms, they provided a route whereby migration of contaminants into
Lauritzen Canal sediments has continued. Current data on the concentrations of
contaminants in the canal sediments are needed to determine the immediate and near-term effect on contaminant concentrations in sediment of excavating the embankment.

Heavy metals and chlorinated pesticides such as DDT, endrin, and dieldrin persist in the
environment and in fatty tissues of organisms, so they have accumulated up to toxic
levels in benthic organisms in the Lauritzen Canal. Bioaccumulation of DDT appears
to be occurring in fish that may migrate into the canal to feed on the surviving benthic
organisms, and then migrate to the Santa Fe Channel and Richmond Inner Harbor.

Migratory ducks that winter on Brooks Island, which is just outside the Richmond
harbor, are known to bioaccumulate DDE, a metabolite of DDT, during their stay from
January to March, apparently from feeding on fish in Richmond harbor, which contain
DDT and DDE. Therefore, people who eat fish that migrate into the Lauritzen Canal
to feed may also accumulate DDT or its persistent metabolites.

Recent activity on the site appears to have disturbed the top layer of gravel, and may be
generating dust containing DDT and heavy metals. That may result in increased
generation of soil dust containing DDT and heavy metals with subsequent deposition
on the skin, and inhalation and ingestion of contaminated dust by on-site workers who
were observed eating lunch on site. Chlorinated pesticides and heavy metals accumulate
in tissues of exposed persons and in other organisms. Previous air monitoring was
performed when the site was inactive; therefore, the levels measured may not reflect
current conditions.

DDT, endrin, dieldrin, and heavy metals such as lead may have migrated off site in
airborne dust to the residential community north of the site. The dust containing DDT
and heavy metals may have been deposited in the soils of the neighborhood where
children may play and adults may garden.

The data available for review at this time are insufficient to fully characterize potential health risks.

RECOMMENDATIONS

Take necessary action to enforce the order against working on that part of the
LTRC property constituting the contaminated United Heckathorn National
Priorities List Superfund Site, unless monitoring of airborne dust generated
while heavy vehicles operate over contaminated parts of the site demonstrates
that levels of chlorinated hydrocarbons and heavy metals are not a concern for
on-site workers or off-site migration of contaminants.

Request that the contractor for the LTRC, and other potentially responsible
parties, analyze for DDT, other chlorinated pesticides, and heavy metals in
benthic organisms from the Lauritzen Canal, and in fish that migrate into the
Lauritzen Canal, the Santa Fe Channel, Richmond Harbor, and waters around
Brooks Island.

Post warnings in English, Spanish, Laotian, Vietnamese, and in pictograms
against fishing in the Lauritzen Canal and water side of the channel.

Talk with Richmond neighborhood community leaders to identify and warn
people who may be doing subsistence fishing in the area. Identify Asian groups
for whom fish and benthic organisms may constitute a large portion of the diet.

Take samples of soils in the residential neighborhood and analyze for DDT,
other chlorinated pesticides and heavy metals to determine the extent of surface
soil contamination.

If surface soil contamination is significant, and air concentrations on-site exceed
those found when the site was inactive, monitor air in the residential community
to determine current airborne levels of heavy metals and DDT.

Further environmental characterization and sampling of the site and of affected
off-site areas during the Remedial Investigation and Feasibility Study should be
designed to address the environmental and human exposure pathways discussed
in this report.

Health Activities Recommendation Panel (HARP) Recommendation

The United Heckathorn site has been evaluated by ATSDR's HARP for follow-up health
activities. Although exposure to site contaminants is believed to have occurred in the past and
may be occurring currently, environmental sampling data are not available to assess the
magnitude and public health significance of the exposure. Therefore, this site is not being
considered at this time for follow-up health activities. However, when these data become
available, ATSDR and the California Department of Health Services will re-evaluate this site for any indicated follow-up activities.

PUBLIC HEALTH ACTIONS

Public Health Actions Planned

Based on the recommendation of HARP, ATSDR is not planning any follow-up health activities
at this time. However, CDHS will cooperate with appropriate state agencies to post warnings
in different languages and with pictograms against fishing on the Lauritzen Canal and water side
of the channel. Community relations staffmembers within CDHS and EPA will continue
community relations activities with the Richmond community, sharing information about the
site and warning people against fishing in the area. Additionally, EPA has indicated that they
plan to take the actions listed below, which are related to the recommendations in the
preliminary health assessment.

1. EPA will consider including in the workplan for the Remedial Investigation/Feasibility Study
additional analyses of fish and benthic organisms from the Lauritzen Canal, Santa Fe Channel,
Richmond Harbor, and waters around Brooks Island for DDT, other chlorinated pesticides, and
heavy metals.

2. EPA will consider taking samples of soil in the residential neighborhood and monitoring air
levels for DDT, other chloriated pesticides, and heavy metals.

3. EPA will continue working with potentially responsible parties to fully characterize the site
and to decrease exposures for on-site workers.

CDHS and ATSDR will coordinate with the appropriate agencies regarding actions to be taken
in response to those recommendations provided in this preliminary health assessment, and for which no plan of action has yet been developed.

*Before 7/19/91, the Hazardous Waste Toxicology Section was a section
under the Environmental Epdemiology and Toxicology Branch within the
California Department of Health Services.

CERTIFICATION

This preliminary public health assessment was prepared by the California Department of Helath
Services under a cooperative agreement with the Agency for Toxic Substances and Disease
Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the public health assessment was initiated.

Burt J. Cooper
Technical Project Officer, SPS, RPB, DHAC

The Division of Health Assessment and Consultation, ATSDR, has reviewed this preliminary public health assessment, and concurs with the findings contained in it.

Director, DHAC, ATSDR

APPENDIX A: INHALATION OF CONTAMINATED
AIRBORNE DUST IN THE RESIDENTIAL NEIGHBORHOOD NEAR UNITED HECKATHORN

A calculation has been performed to determine if excess risks from inhalation of DDT in dust
exists at the levels reported in Ecology and Environment's "Determination of Organochlorine
Pesticides and Polychlorinated Biphenyls in Ambient Air," 1989. The following equation was used: Risk = CDI x SF

where risk is a unitless probability of a person developing cancer. It is expressed as the "Life-time excess cancer risk per million people."

CDI is the chronic daily intake or exposure averaged over 70 years, expressed as mg/kg-day. SF is the slope factor, expressed in (mg/kg-day)-1.

Since test animals receive high doses compared to usual environmental exposures, a linear dose-response slope is extrapolated down to low-doses using a multistage model for cancer
development. The SF, or q1*, is an estimate of the potency of the compound based on the
number of tumors induced in animals. It is the 95 percent upper confidence level of the value
obtained by calculating the slope from the number of tumors observed at each dose level in the
animal studies. It is specific for each compound and is found in the EPA's Integrated Risk
Management System (IRIS). The potency values of the two compounds classified as probable
carcinogens are 3.4 x 10-1 for DDT, and 1.6 (mg/kg-day)-1 for Dieldrin.

Chronic Daily Intake is calculated from measured or estimated environmental media
concentrations, physiological and physical factors that influence exposure, and duration of
exposure. The calculation and the factors used in the calculations of Chronic Daily Intake are
discussed below.

where CA is the contaminant concentration in the air in mg/m3. The air monitoring data
given in the sections on On-Site Contaminants and Off-Site Contaminant concentration
were converted from ng/m3 to mg/m3 by the factor 1 mg /1 x 106 ng. The exposure values
for DDT are the averages for DDD, DDE, and DDT, which were summed to derive the
Total DDT concentration (Table 6).

IR is the inhalation rate, 20 m3/day for adults normally, 30 m3/day during heavy
work or jogging.

ET is exposure time in hours/day, assumed to be 24 hours/day for residents and
8 hours/day for workers.

EF is the exposure frequency. In the case of residents it may be 365 days/year,
while workers may be exposed for only 5 days/week, or 260 days/year.

ED is the exposure duration, usually estimated as 70 years.

BW is body weight, given as 70 kg for an adult, and 15 kg for a child.

AT is the averaging time, which for carcinogenic effects is 70 years x 365
days/year

The standard equation for risk calculations is used here to estimate the lifetime risk for
residents in the neighborhoods north of the site who may have inhaled or who may inhale
airborne contaminants. This is only an estimate, since the exposure levels are assumed to remain constant over a 70 year lifetime, and a standard adult weight of 70 kg is used.

A calculation has been performed to estimate if excess risks from ingesting fish containing DDT exist
at the levels reported in the limited samples caught by United Anglers and analyzed by the California
Department of Fish and Game. The following equation was used: Risk = CDI x SF

where risk is a unitless probability of a person developing cancer. It is expressed as the "Life-time excess cancer risk per million people".

CDI is the chronic daily intake or exposure averaged over 70 years, expressed as mg/kg-day;

SF is the slope factor, expressed in (mg/kg-day)-1. Since test animals receive high doses
compared to usual environmental exposures, a linear dose-response slope is extrapolated down
to low-doses using a multistage model for cancer development. The SF, or q1*, is an estimate
of the potency of the compound based on the number of tumors induced in animals. It is the 95
percent upper confidence level of the value obtained by calculating the slope from the number
of tumors observed at each dose level in the animal studies. It is specific for each compound and
is found in the EPA's Integrated Risk Management System (IRIS). The value for the potency of DDT is 3.4 x 10-1.

Chronic daily intake is calculated from measured or estimated environmental media concentrations,
physiological and physical factors that influence exposure, and duration of exposure. The calculation
and the factors used in the calculations of chronic daily intake are discussed below.

where CA is the contaminant concentration in the fish and/or shellfish in
mg/kg.

IR is the ingestion rate which varies with lifestyle factors, geographic location and socio-ethnic
origin. CDHS has used 22 g/day for the average Californian, but this value is considered low
for current fish consumption because it allows only one small fish meal per week. Thirty-eight
g/day is the 50th percentile daily intake and 132 g/day is the 95th percentile for daily intake
according to the EPA Risk Assessment Guidance for Superfund, 1989.

FI is the fraction ingested from the contaminated source, which is estimated to be 50 percent of
the fish in this risk assessment.

EF is the exposure frequency. It is pathway specific and should consider local population
patterns if such information is available. The 1989 EPA TOlerance Assessment System
estimates 48 days/year to be the average amount per capita for fish and shellfish consumption.
The exposure frequency is 365 days/year if daily intake values of 23 g/day to 132 g/day are
used.

ED is the exposure duration, usually estimated as 70 years.

BW is body weight, given as 70 kg for an adult, and 15 kg for a child.

AT is the averaging time, which for carcinogenic effects is 70 years x 365 days/year.

The standard equation for risk calculations is used here to estimate the lifetime risk for neighborhood
residents who may catch and eat fish and shellfish from the Richmond Harbor area. This estimate is
based on very limited data on DDT contamination levels in fish. This is only an estimate, because the
exposure levels are assumed to remain constant over a 70 year lifetime, and a standard adult weight of
70 kg is used.

Therefore, the excess risk associated with eating fish near United Heckathorn
is 3.7 X 10-3.

APPENDIX C: RESPONSES TO PUBLIC COMMENTS
ON THE SEPTEMBER 1991 DRAFT PRELIMINARY HEALTH ASSESSMENT

Response: The California Department of Health Services (CDHS) has prepared this Preliminary Health
Assessment for the United Heckathorn site under a cooperative agreement with the Agency for Toxic
Substances Disease Registry (ATSDR). Under the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA) and the 1986 Superfund Amendments and
Reauthorization Act (SARA), ATSDR must evaluate the public health significance of hazardous waste
sites by performing specific public health activities associated with actual or potential exposure to
hazardous substances released into the environment. ATSDR must conduct health assessments on all
sites added to the National Priorities List (NPL) since October 17, 1986, within one year of a listing (or
being proposed for listing).

As with the United Heckathorn site, CDHS and ATSDR will designate as "preliminary" those health
assessments prepared on sites for which site characterization is incomplete, or for which there is no
summary of relevant health outcome data or environmental data. For the United Heckathorn
Preliminary Health Assessment, CDHS and ATSDR evaluated data primarily available when the site
was initially proposed for inclusion on the NPL. Information utilized was obtained from state
administrative files, federal agency reports, site visits, and consultations with involved agencies and with
the public. Designating a health assessment as preliminary conveys to EPA, the state, and the public
that CDHS and ATSDR have conducted the assessment based upon limited data. For sites receiving
a preliminary health assessment, a further health assessment will be performed, if considered
appropriate, when the full environmental characterization is completed, usually in the form of a
Remedial Investigation Feasibility Study and Baseline Risk Assessment, and provided to ATSDR for
consideration.

To assist with the development of health assessments, ATSDR has developed guidance materials,
including a Health Assessment Guidance Manual, decision statements, and toxicological profiles. States
preparing health assessments under cooperative agreement with ATSDR must utilize the format and
include appropriate content as outlined in these guidance materials. All health assessments undergo a
rigorous review by scientists and technical people within CDHS, ATSDR, EPA, and other appropriate
agencies before being released for public comment. CDHS and ATSDR welcomes additional
infomation from any party who wishes to submit it to us and will make revisions as we deem
appropriate.

CDHS and ATSDR have revised the September 1991 Draft Preliminary Health Assessment based on
public comments that supported with adequate documentation. CDHS and ATSDR appreciate the time
and effort spent by citizens and organizations who commented on the assessment. Many of the
comments resulted in revisions that improved the document. In preparation for conducting a full health
assessment, ATSDR will continue to consider information that the public may wish to send us regarding
community health issues associated with the United Heckathorn site. In the meantime, the conclusions
expressed in the September 1991 Draft Preliminary Health Assessment represent CDHS and ATSDR's
position on the information available at the time. CDHS and ATSDR stand by the conclusions
presented in the September 1991 document.

2. Comment: The PHA ignores current data on pesticide concentrations on the site following
remedial actions taken in Fall 1990 and April 1991.

Response: CDHS and ATSDR have evaluated data currently available in state administrative files, in
federal agency reports, and in information submitted to CDHS during the public comment period.
Staffers consider information gathered during site visits or during meetings or contacts with involved
agencies and with the public.

Only information regarding pre-remediation concentrations was available to us during the development
of the preliminary health assessment. This information is important to include from a historical
perspective, especially in characterizing past exposures which may have past, current or future public
health implications. ATSDR and CDHS thank all those who offered comments or who provided
additional information. We will review all additional information not available at the time of the
development of this preliminary health assessment when a full health assessment is prepared. (see
response to Comment #1.)

3. Comment: PHA does not contain an adequate analysis of toxicity, dose, and exposure.

Response: CDHS and ATSDR agree that further information is required to determine potential health
risks. However, based on the information available, CDHS and ATSDR evaluated the potential public
health risks from short-term, intermediate-term, and long-term exposure to site-related contaminants
found in different media, and we do not agree with the commentator. Our conclusions are based on
published studies in the fields of epidemiology and toxicology, and on recommended environmental
exposure levels endorsed by the Agency.

4. Comment: Available research does not support the CDHS conclusion that DDT, aldrin and
dieldrin pose serious threats to human health.

Response: CDHS and ATSDR appreciate the additional information provided. As stated previously,
our conclusions are based on published studies in the fields of epidemiology and toxicology, and on
recommended environmental exposure levels endorsed by the Agency. These studies show that EPA
classifies DDT, aldrin, and dieldrin as probable carcinogens in human beings based on animal studies
(B2 carcinogen). IARC and NTP similarly classify DDT as "reasonably anticipated carcinogen."
Additionally, there are documented non-carcinogenic health effects associated wtih DDT, aldrin, and
dieldrin, and which must be considered, as described in the Public Health Implications section.

5. Comment: Assuming that persons are exposed to DDT from the site, existing data suggest any
such exposure is not sufficient to pose a health risk.

Response: CDHS and ATSDR agree that additional data are necessary in order to better
characterize exposures and related health risks, and appreciates receiving additional information.
However, information available for development of the September 1991 draft indicates exposures to
site-related contaminants have occurred in the past and may currently be occurring through multiple
exposure pathways at levels that may pose health concerns. The assumptions made in the PHA are
consistent with the procedures outlined in ATSDR's Health Assessment Guidance Manual. Additional
information will be considered as appropriate during development of a full health assessment.

Response: DDT as a parent compound and DDT's metabolites may be transported through several
media by the processes of adsorption, bioaccumulation, solubilization or volatilization. Volatilization
of DDT and DDE accounts for their considerable losses from soil surfaces and water. Estimates of rates
of DDT, DDE, and DDD losses from water ranging from several hours to 50 hours (Hazardous
Substances Data Base 1988) have been documented. DDT and its metabolites also bioaccumulate in
fresh water and marine plankton, insects, mollusks, other invertebrates, fish and other organisms,
according to the ATSDR 1989 Toxicological Profile for DDT, DDE and DDD. DDT and its
metabolites may also be transported by wind as fugitive dust.

OSHA's Permissible Exposure Levels (PELs) apply to healthy adult employees working 40-hour weeks
and do not apply to the general population (including children, the sick and the elderly) who may have
been subjected to continuous exposure to environmental contaminants from United Heckathorn.
Consequently, air levels below OSHA's PELs may still pose a health concern for certain population
groups. Additionally OSHA's PEL value for DDT is not based on carcinogenicity. The National
Institute of Occupational Safety and Health (NIOSH) identifies DDT as an occupational carcinogen
and recommends that exposure be limited to the lowest feasible concentration.

7. Comment: There are errors in the risk calculations for inhalation of air by off-site receptors, and for
fish ingestion. Additionally, the PHA inappropriately uses input values based on "worst case" scenario,
which differs from EPA's Risk Assessment Guidelines for Superfund.

Response: The references and calculations on the inhalation of airborne dusts and excess risks
associated with eating fish caught near United Heckathorn have been checked and corrected where
appropriate. The data used for calculations on excess risk due to ingestion of fish came from the
Department of Fish and Game and were reviewed by the state staff from the Pesticide Epidemiology and
Toxicology Section. The calculations were based on ATSDR's Health Assessment guidelines and/or
EPA's Risk Assessment Guidance for Superfund. DDT and its metabolites concentrate in lipids. Some
population groups, however, eat raw fish and fish organs as part of their regular diet. Consequently,
using the "worst case" scenario and other averaging values about fish consumption, the excess risk
associated with eating fish was computed. The use of "worst case" and average concentrations based
on site-specific information as scenarios for the analyses are valid and consistent with ATSDR's health
assessment procedures. Following are the corrected risk estimate values identified in Apendices A and
B. For the inhalation of contaminated airborne dust in the residential neighborhood near United
Heckathorn, the DDT excess risk = 1.9 X 10 -7 and the combined average excess risk from DDT +
Dieldrin = 3.1 X 10-7. The excess risk associated with eating fish contaminated only with DDT and
caught near the United Heckathorn site = 2.2 X 10-4. The actual risk may actually be higher for
contaminated fish ingestion if the added risk from dieldrin contamination is considered. According to
the state's Mussel Watch Program, the highest dieldrin levels in fish in the state are found in fish caught
in the Lauritzen Canal.

8. Comment: The toxicity information presented in the assessment is incomplete and/or
unreferenced and, in a number of instances, plainly erroneous.

Response: CDHS and ATSDR appreciate receiving the additional information provided by the
commentators. Where appropriate, we have clarified references to concentrations and doses.
Carcinogenicity information regarding aldrin and dieldrin is taken from EPA, which classifies dieldrin
and aldrin, too, as probable carcinogens in humans (B2) based on animal data. Additionally we use
toxicity information obtained from ATSDR's Toxicological Profiles, EPA's Integrated Risk Information
System (IRIS), and other published studies.

9. Comment: The PHA identifies airborne particulate emissions and ground water seepage into
the Lauritzen Canal as apparently significant contaminant transport pathways. However, the available
data indicate that these migration routes are not very significant and would not lead to significant
chemical exposures. The PHA also identifies inhalation and ingestion exposure to residential soils as
being complete exposure pathways, despite the presence of little or no data to confirm that human
exposures have occured or are currently occuring.

Response: CDHS and ATSDR include as a recommendation in the PHA gathering additional data in
order to better characterize exposure pathways. However, based on the information we have reviewed,
inhalation of airborne contaminants and ingestion of contaminants through consumption of
contaminated fish could pose significant exposure pathways.

10. Comment: Why didn't the state clean the site, given that the site has been a serious health hazard
since 1949?

Response: Available site information we have shows that several agencies have been active in attempts
to clean up the site, but the complex history of the site and the inadequate environmental sampling are
some of the factors that have led to delays in site clean-up. Currently EPA is carrying out a detailed
sampling plan that will allow for a number of clean-up alternatives to be considered.

Response: CDHS and ATSDR agree that ongoing communication is necessary, and have shared this
concern with staff at EPA and the Cal EPA Department of Toxic Substances Control and asked the
community relations staff at EPA to consider this request.

12. Comment: Was the community notified of soil removal on the site? What precautionary measures
were taken to provide public safety? What means were used to insure that no ingestion of the soil would
occur?

Response: Different government agencies have been involved with soil removal activities on the site.
A number of fact sheets were developed and distributed by the different regulatory agencies to inform
the community of the proposed activities. Questions about soil removal activities that took place under
the direction of the California Regional Water Quality Control Board should be directed to their
Community Relations Coordinator in Oakland at (510) 464-1255. Questions about removal activities
that occurred under the direction of the California Department of Toxic Substances Control can be
directed to their Community Relations Coordinator at (510) 540-2122. Questions about clean-up
activities under EPA, the regulatory agency now in charge of the site's clean-up, can be directed to
Norman Calero, Community Relations Coordinator, US EPA, 75 Hawthorne St. (H-1-1), San
Francisco, CA 94105, phone (415) 744-2183 or 1-800-231-3075. EPA also maintains an
administrative record including all documents upon which EPA bases the decision for a removal action
a site. Copies of the administrative record are available for public review at the Richmond Public
Library, 325 Civic Center Plaza, Richmond, CA 94804. EPA prepares a Health and Safety Plan for
all emergency removal actions. (See response to #16 below.)

13. Comment: Have the communities been screened for possible coronary diseases or respiratory
diseases as a result of the contaminated material being in the community?

Response: To our knowledge, no health screenings related to the site contaminants have been conducted
for the communities. The Health Activities Recommendation Panel within ATSDR has reveiwed the
draft preliminary health assessment and is not currently recommending follow-up health activities. As
environmental sampling data become available to assess the magnitude and public health significance
of the exposure, ATSDR and CDHS will reevaluate the site for any indicated follow-up health activities.

14. Comment: What can be done about other airborne particles that pollute the air, and which might
be coming from some of the existing activities around the site?

Response: Routine air monitoring to determine overall air quality is the responsibility of the Bay Area
Air Quality Management District and is not usually considered part of the Superfund clean-up process.
If required by health and safety procedures, air monitoring can be conducted during investigation and
clean-up.

Recommendations were included in the preliminary health assessment for conducting air monitoring
to better quantify site-related contaminants. Current air monitoring results may not reflect air
contaminant concentrations that may have resulted from past site operations.

15. Comment: The community should have top priority with regards to safety, public health, long term
prognosis, air sampling, community awareness, preventive measures, and health risks associated with
whatever amount of exposure. If evacuation is advised, effects on the community (housing costs,
additional travel to work and school) need to be considered.

Response: As the agency overseeing current clean-up activities, EPA is developing a community
relations plan. For all emergency removal actions, EPA requires the preparation of a health and safety
plan to ensure no releases of contaminants to the surrounding community occur during the removal.
The community will also be given the opportunity to comment on the proposed clean-up plan.
Recommendations and findings from CDHS and ATSDR regarding the pulbic health significance of
the site are routinely shared with the community, EPA, and other appropriate agencies to assist with
development of clean-up procedures.

16. Comment: The health assessment should take into account any and all potential health effects
caused by the site on the community and biota.

Response: CDHS and ATSDR have described past and present complete human exposure pathways
in Table 9 of the preliminary health assessment. Past exposures may result in present or future health
effects. More data are needed to determine the actual exposure concentrations. When these data
become available, better characterization of health effects will be possible, and the public health
significance of the site can be better defined.

17. Comment: The contaminated material and clean-up at United Heckathorne should be handled with
great care and the material kept track of, including where it gets disposed of.

Response: Federal regulations require that clean-up measures protect human health and the
environment, and will include procedures for and documentatation of proper handling and disposal of
contaminated material. (See response to comments #11 and #14, above.)